Prostate Cancer Genome Offers New Treatment Target

Gene mutations found in some patients provide hope for new and existing treatments.

Prostate cancer patients who have a genetic abnormality may be more susceptible to new and existing therapies, a recent study indicates.

The study, published in the May 21, 2015 edition of Cell, analyzed tumor samples from 150 metastatic prostate cancer patients who did not respond to current treatments that block hormones. The current study was the first to evaluate the genomic characteristics of metastatic hormone resistant prostate cancer. This cancer type is tough to treat due to the development of resistance to standard treatments.

"This study provides a strong argument that the genomics driving advanced prostate cancer is fundamentally different than primary prostate cancer, and that knowledge of these genomic differences may be immediately clinically actionable for patients with advanced disease," first author Eliezer Van Allen, MD, said in a press release.

Most of the tumors examined in the study carried at least 1 genetic aberration that fuels most types of cancer. The most common of these aberrations, found in the genes responsible for the androgen receptor, was detected in approximately two-thirds of tumor samples.

This finding was expected, as the primary characteristic of castration-resistant prostate cancer is no longer responding to standard androgen-blocking therapies. However, numerous other aberrations were revealed.

Approximately one-fourth of patients had mutations in the BRCA1 or BRCA2 genes, which increase the risk of breast and ovarian cancers. The study showed approximately 8% of patients carry the inherited gene abnormality, which indicates genetic counseling may be effective for prostate cancer patients.

"This is a landmark paper in several respects," senior study author Philip Kantoff, MD, in a press release. "It represents a model of collaboration between cancer centers, represents a monumental operational, technical and computational achievement and finally represents the value of precision medicine in finding actionable mutations."